Over the past few decades, there's been a revolution in caring for children with congenital heart defects. Advances in diagnosis and surgery have made it possible to fix or repair most defects, even those once thought to be hopeless. Many people with these defects are now reaching adulthood and living full, active lives. However, no two people are the same. Your doctor can advise you about your specific heart defect. 

The Normal Heart and How it Works

The normal heart is a pump made of muscle tissue. It's about the size of your fist. The heart has four chambers. The two upper ones are the atria, and the lower two are the ventricles. Four heart valves open and close to keep the blood flowing in one direction as it's pumped through the heart.

The four heart valves are:

• tricuspid valve - located between the right atrium and the right ventricle
• pulmonary (pulmonic) valve - between the right ventricle and the pulmonary artery
• mitral valve - between the left atria and the left ventricle 
• aortic valve - between the left ventricle and the aorta

Each valve has a set of "flaps" (also called leaflets or cusps). The mitral valve normally has two flaps; the others have three.

Dark bluish (oxygen-poor) blood returns to the heart after circulating through the body. It flows to the heart through veins and enters the right atrium. This chamber empties blood through the tricuspid valve into the right ventricle. The right ventricle pumps blood under low pressure through the pulmonary valve into the pulmonary artery. From there the blood goes to the lungs, where it gets fresh oxygen. Oxygen-rich blood is bright red . Now the blood returns to the left atrium. From there it passes through the mitral valve and enters the left ventricle.

The left ventricle pumps the red, oxygen-rich blood through the aortic valve and into a large artery called the aorta. The aorta takes blood from the heart to the rest of the body. The blood pressure in the left ventricle is the same as in the arm. While passing through the body, oxygen in the blood is distributed to the tissues. The cycle repeats as the blood flows back to the right atrium.

What is Congenital Heart Disease?

Congenital Heart Disease is a result of a disease or disorder of the heart that develops before birth, as opposed to heart disease which can develop as a person ages. Congenital heart defects are the most common type of birth defect, and occur in about 1% of all live births.

What Causes Congenital Heart Disease?

A specific cause for congenital heart disease is unknown, but research has established several potential contributors to heart defects, including:

• Heredity - Sometimes, but rarely, the defect is genetic.
• Other medical conditions - Congenital birth defects such as Down's syndrome can involve the heart as well as other organs.
• Medications - Some over-the-counter and prescription medications taken by a pregnant woman can cause a congenital heart defect in her unborn baby.
• Alcohol and/or drug use - Alcohol use or the use of illegal drugs during pregnancy can cause birth defects.

Types of Congenital Heart Defects

There are several types of heart defects, with various conditions related to each type. Development, symptoms and treatment vary by type.

• Patent ductus arteriosus (PDA)  
• Obstruction defects
• Septal defects
• Cyanotic defects  
• Hypoplastic left heart syndrome

Preventing Birth Defects

Although doctors have not found one specific cause for congenital heart defects, certain behaviors have been identified as possible contributors. Pregnant women, as well as women planning to become pregnant, can do the following to help prevent birth defects such as congenital heart defects:

• Stop smoking
• Avoid drinking alcohol while pregnant
• Take a daily vitamin containing folic acid
• Check with your doctor to make sure any medication (over-the-counter or prescription) is safe to take during pregnancy
• Stop use of any illegal or "street" drugs